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As explained above, the viewing of moving-picture content via the Internet is becoming a common practice. With this background, TV Bank Corporation has developed a system named “BBbroadcast”-a system that can send video content to multiple users simultaneously-in an aim to promptly establish a video content distribution business. The three features are shown below.
Feature 1: Achievement of both low cost and large-scale distribution
 Graph presenting relationship between number of simultaneous viewers and cost |
Use of the BBbroadcast system enables the distribution of moving-picture content to tens of thousands of users simultaneously at a low cost through the broadband network. On “Yahoo! Streaming,” a video content portal provided by Yahoo Japan Corporation, a live performance by EXILE, a popular dance and vocal unit, was experimentally sent on September 22, 2006, at the high bit rate of 768 kbps. This experiment attained a maximum of 25,302 viewers at the same moment, at a cost of approximately 1/5 of the Unicast distribution (based on calculation by our company), which is a popular video content distribution method. |
Feature 2: Restraining of rapid traffic increases
| In recent years, there is rising concern that Internet Service Providers (ISP) will be overwhelmed by the cost boost caused by rapid traffic increases, and that it will not be long before the telecommunication infrastructure in Japan collapses. ISPs must upgrade equipment and increase transit payments in correspondence with traffic increases. In the process of an ordinary Unicast distribution, data conforming to the number of users is sent from (1)→(2)→(3). In the case of the BBbroadcast system, which is a system that can send video content to multiple users simultaneously, users below (3) will largely provide the data necessary for video content viewing. For this reason, traffic between (1) and (2) can be reduced while traffic at (3) is maintained at the level of Unicast distribution. Wide prevalence of the BBbroadcast system will contribute to the sustaining and development of the Internet, a social infrastructure, by restraining ISP transit costs and capital investment, while imposing no limitation on user access to video content. | |
An ordinary ISP network (1) “Transit” that connects Internet exchange points (IX) among providers and other ISPs. (2) “Backbone” that connects connection points within ISP. (3) “Access network” that connects households of users in various regions. |
Feature 3: Credible content protection
BBbroadcast manages content to which Digital Rights Management (DRM) of Microsoft Corporation’s Windows Media applies at the provider’s server, and sends the data after encryption. Each user’s personal computer sends encrypted data to the next user. Additionally, video content distribution by the BBbroadcast system is streaming (sequential reproduction) delivery. Since all data processing is performed in memory, no content data is saved on the user’s personal computer.
On the other hand, concerning user security, there is absolutely no danger of information leakage from personal computer storage because unjust data is disposed of upon reception, and there is no function to read hard disc data or send the user’s own content. Additionally, BBbroadcast has been subject to strict security audits by LAC (Little eArth Corporation Co., Ltd.).
(1) Unicast and Multicast
The most popular video content distribution technology using the Internet is Unicast. “Uni-” means “single.” The Unicast system, as the name explains, sends data from the distributor to a specific user. For example, when three users are watching the same video content, the distributor must respectively send each user the data. Therefore, the amount of data sent from the distributor will increase in relation to the number of users, and result in large investment cost for the distributor and increased load over the network to the users’ homes. This system is introduced in the Video on Demand (VOD) systems in which users can watch any video content at any time.
 Unicast and Multicast |
Meanwhile, Multicast solves the issue of large investment cost for the distributor and increased load over the network to the users’ homes. “Multi-” comes from “multiple.” This technology delivers data to large numbers of specific users without imposing a large burden on the network. This is attained by copying and branching off data output from the server as needed, at routers in the midstream. This technology is applied to “IP multicast broadcasting” by which a program can be viewed by connecting a receiver called a Set-top box (STB) to the television. However, because all routers between the distributor and the users’ homes must conform to Multicast technology, costs will become necessary for placement. Additionally, differing from Unicast, there is difficulty in transiting the different networks between Internet Service Providers (ISP). |
(2) New technology of the BBbroadcast system
BBbroadcast adopts technology named Overlay Multicast (OLM) or Application Layer Multicast, which is the advanced version of Multicast. Multicast implements processes carried out by routers-such as checking destinations of data transmission, copying and selecting transmission routes-at the third network layer of the OSI reference model. The OLM system carries out these processes in personal computers at the seventh application layer of the OSI reference model. With this precondition, data is re-sent in Unicast form to personal computers of a number of other users to overcome the network differences among Internet Service Providers (ISP), and thus attains simultaneous data transmission to large number of users.
| With this OLM technology as the foundation, BBbroadcast has enabled simultaneous video content delivery to massive numbers of users through the broadband network without large-scale equipment, by assuring multilateral transmission routes, introducing technology to stably receive data, and technology to protect content by segmentalizing it. |  Mesh-type network |
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